Visible Cascade Higgs Decays to Four Photons at Hadron Colliders

The presence of a new singlet scalar particle a can open up new decay channels for the Higgs boson, through cascades of the form h -> 2a -> X, possibly making discovery through standard model channels impossible. If a is CP-odd, its decay products are particularly sensitive to physics beyond the standard model. Quantum effects from heavy fields can naturally make gluonic decay, a -> 2g, the dominant decay mode, resulting in a h -> 4 g decay which is difficult to observe at hadron colliders, and is allowed by LEP for m_h > 82 GeV. However, there are usually associated decays with photons, either h -> 2g 2gamma or h -> 4gamma, which are more promising. The decay h -> 2g 2gamma only allows discovery of the a particle and not the Higgs whereas h -> 4gamma is a clean channel that can discover both particles. We determine what branching ratios are required for discovery at LHC and find that with 300 fb^-1 of luminosity, a branching ratio of order 10^-4 is sufficient for a large region of Higgs masses. Due to a lower expected luminosity of ~ 8 fb^-1, discovery at the Tevatron requires more than 5 x 10^-3 in branching ratio.Comment: 6 pages, 2 color figures, revtex4 forma

Red Crossbill Invasion of Northwestern Arkansas during 2012-2013

An irruption of Red Crossbills (Loxia curvirostra) occurred in primarily northwestern Arkansas starting in November of 2012 and lasting to the end of May of 2013. Based on recordings of call notes, most birds around Fayetteville were Type 2, the large-billed ponderosa pine crossbill, associated with a variety of conifer species. Birds recorded in Carroll County were Type 3, the small-billed western hemlock crossbill, and they were associated with small cones on shortleaf pine (Pinus echinata). One recording was obtained in Fayetteville of Type 5, the lodgepole pine crossbill, only the third recording east of the Great Plains. Crossbills at the Fayetteville Country Club were observed eating algae (Cladophora sp.) during the months of December and January, a behavior rarely reported for passerines. During March, crossbills appeared at sunflower bird feeders, which is a relatively recent phenomenon associated with low conifer seed abundance. The first two Arkansas specimens of crossbills (probably Type 3) were obtained from birds that struck windows near feeders. This is only the third recorded irruption of crossbills in Arkansas in the last 43 years, suggesting that crossbills rarely travel this far south in search of cone crops

Subscriber churn in the Australian ISP market

Rapid growth in Internet use, combined with easy market entry by Internet service providers (ISPs), has resulted in a highly competitive supply of Internet services. Australian ISPs range in size from a few large national operators to niche ISPs focused on specialised service. With many ISPs currently not profitable, subscriber retention is an important aspect of survival. This study develops a model which relates the probability of subscriber churn to various service attributes and subscriber characteristics. Estimation results show that churn probability is positively associated with monthly ISP expenditure, but inversely related to household income. Pricing also matters with subscribers preferring ISPs which offer flat-rate pricing arrangements.

Strengths and Silences: The Experiences of Lesbian, Gay, Bisexual and Transgender Students in Rural and Small Town Schools

For more than 20 years, GLSEN has worked to make schools safer for all students; it has sought specifically to reduce the bullying and harassment targeted at students' sexual orientation, gender identity, and gender expression. For lesbian, gay, bisexual, and transgender (LGBT) students across the country, violence and harassment experienced in school affect their ability to learn. Although schools in urban areas are typically regarded as more violent or dangerous than schools in other areas, findings from our National School Climate Surveys consistently show that it is most often rural schools that may pose the greatest threats for LGBT students. It may be that community characteristics, such as religious and cultural traditions, income, and educational levels, influence individual beliefs and attitudes toward LGBT people in these areas. It may also be that a lack of positive LGBT-related school resources negatively affects LGBT students' school engagement and academic performance, particularly if they also experience bullying and harassment. Although research on the educational experiences of LGBT youth has grown considerably over the past 25 years, less is known about rural students specifically. This research report examines the experiences of LGBT students in small town and rural areas on matters related to biased language in schools, school safety, harassment and victimization, educational outcomes, school engagement, and LGBT-related resources and support. It also examines the prevalence and utility of LGBT-related resources in rural schools. Finally, this report concludes by advocating for more intentional policies, measures, and programs that protect LGBT students

Statistical properties of fractures in damaged materials

We introduce a model for the dynamics of mud cracking in the limit of of extremely thin layers. In this model the growth of fracture proceeds by selecting the part of the material with the smallest (quenched) breaking threshold. In addition, weakening affects the area of the sample neighbour to the crack. Due to the simplicity of the model, it is possible to derive some analytical results. In particular, we find that the total time to break down the sample grows with the dimension L of the lattice as L^2 even though the percolating cluster has a non trivial fractal dimension. Furthermore, we obtain a formula for the mean weakening with time of the whole sample.Comment: 5 pages, 4 figures, to be published in Europhysics Letter

Quantitative multielement analysis using high energy particle bombardment

Charged particles ranging in energy from 0.8 to 4.0 MeV are used to induce resonant nuclear reactions, Coulomb excitation (gamma X-rays), and X-ray emission in both thick and thin targets. Quantitative analysis is possible for elements from Li to Pb in complex environmental samples, although the matrix can severely reduce the sensitivity. It is necessary to use a comparator technique for the gamma-rays, while for X-rays an internal standard can be used. A USGS standard rock is analyzed for a total of 28 elements. Water samples can be analyzed either by nebulizing the sample doped with Cs or Y onto a thin formvar film or by extracting the sample (with or without an internal standard) onto ion exchange resin which is pressed into a pellet

Subscriber churn in the Australian ISP market

Rapid growth in Internet use, combined with easy market entry by Internet service providers (ISPs), has resulted in a highly competitive supply of Internet services. Australian ISPs range in size from a few large national operators to niche ISPs focused on specialised service. With many ISPs currently not profitable, subscriber retention is an important aspect of survival. This study develops a model which relates the probability of subscriber churn to various service attributes and subscriber characteristics. Estimation results show that churn probability is positively associated with monthly ISP expenditure, but inversely related to household income. Pricing also matters with subscribers preferring ISPs which offer flat-rate pricing arrangements.Internet; customer churn; pricing

Study of a heat rejection system using capillary pumping

Results of an analytical study investigating the application of capillary pumping to the heat rejection loop of an advanced Rankine cycle power conversion system are presented. The feasibility of the concept of capillary pumping as an alternate to electromagnetic pumping is analytically demonstrated. Capillary pumping is shown to provide a potential for weight and electrical power saving and reliability through the use of redundant systems. A screen wick pump design with arterial feed lines was analytically developed. Advantages of this design are high thermodynamic and hydrodynamic efficiency, which provide a lightweight easily packaged system. Operational problems were identified which must be solved for successful application of capillary pumping. The most important are the development of start up and shutdown procedures, and development of a means of keeping noncondensibles from the system and of earth-bound testing procedures

The 2011 National School Climate Survey: The Experiences of Lesbian, Gay, Bisexual and Transgender Youth in Our Nation's Schools

In 1999, GLSEN identified the need for national data on the experiences of lesbian, gay, bisexual, and transgender (LGBT) students and launched the first National School Climate Survey (NSCS). At the time, the school experiences of LGBT youth were under-documented and nearly absent from national studies of adolescents. For more than a decade, the biennial NSCS has documented the unique challenges LGBT students face and identified interventions that can improve school climate. The survey explores the prevalence of anti-LGBT language and victimization, the effect that these experiences have on LGBT students' achievement and well-being, and the utility of interventions in lessening the negative effects of a hostile school climate and promoting a positive educational experience. The survey also examines demographic and community-level differences in LGBT students' experiences.The NSCS remains one of the few studies to examine the school experiences of LGBT students nationally, and its results have been vital to GLSEN's understanding of the issues that LGBT students face, thereby informing our ongoing work to ensure safe and affirming schools for all.In our 2011 survey, we examine the experiences of LGBT students with regard to indicators of negative school climate:hearing biased remarks, including homophobic remarks, in school;feeling unsafe in school because of personal characteristics, such as sexual orientation, gender expression, or race/ethnicity;missing classes or days of school because of safety reasons; andexperiencing harassment and assault in school.We also examine:the possible negative effects of a hostile school climate on LGBT students' academic achievement, educational aspirations, and psychological well-being;whether or not students report experiences of victimization to school officials or to family members and how these adults address the problem; andhow the school experiences of LGBT students differ by personal and community characteristics.In addition, we demonstrate the degree to which LGBT students have access to supportive resources in school, and we explore the possible benefits of these resources, including:Gay-Straight Alliances (GSAs) or similar clubs;anti-bullying/harassment school policies and laws;supportive school staff; andcurricula that are inclusive of LGBT-related topics.Given that GLSEN has more than a decade of data, we examine changes over the time on indicators of negative school climate and levels of access to LGBT-related resources in schools

Review: emerging concepts in the pathogenesis of tendinopathy

Tendinopathy is a common clinical problem and has a significant disease burden attached, not only in terms of health care costs, but also for patients directly in terms of time off work and impact upon quality of life. Controversy surrounds the pathogenesis of tendinopathy, however the recent systematic analysis of the evidence has demonstrated that many of the claims of an absence of inflammation in tendinopathy were more based around belief than robust scientific data. This review is a summary of the emerging research in this topical area, with a particular focus on the role of neuronal regulation and inflammation in tendinopathy